Shareholder Report, Line Graph (Details) 190997_Buffalo Early Stage Growth Fund_Investor Class_TSR Annual {Investor Class} - USD ($) |
12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Mar. 31, 2023 |
Mar. 31, 2022 |
Mar. 31, 2021 |
Mar. 31, 2020 |
Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
Mar. 31, 2016 |
Mar. 31, 2026 |
|
| Investor Class | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Buffalo Early Stage Growth Fund Investor Class | ||||||||||
| Accumulated Value | $ 22,047 | $ 23,848 | $ 22,210 | $ 25,896 | $ 29,877 | $ 14,036 | $ 16,392 | $ 14,985 | $ 12,299 | $ 10,000 | $ 23,943 |
| Russell 3000 Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 3000 Index | ||||||||||
| Accumulated Value | 30,620 | 28,558 | 22,088 | 24,161 | 21,587 | 13,282 | 14,616 | 13,438 | 11,807 | 10,000 | $ 36,157 |
| Russell 2000 Growth Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Russell 2000 Growth Index | ||||||||||
| Accumulated Value | $ 20,587 | $ 21,638 | $ 17,980 | $ 20,111 | $ 23,474 | $ 12,342 | $ 15,158 | $ 14,596 | $ 12,303 | $ 10,000 | $ 25,440 |